Halo-phosphorus compounds and process for their preparation



United States Patent O 3,346,669 HALO-PHOSPHORUS COMPOUNDS AND PROCESS FOR THEIR PREPARATION Erik Regel, Mission, Kans., assignor to Chemagro Corporation, Kansas City, Mo., a corporation of New York No Drawing. Filed Apr. 6, 1964, Ser. No. 357,761 18 Claims. (Cl. 260-960) This invention relates to a novel class of chemical compositions characterized in that they are alpha-halo containing phosphonochloridothioates and phosphinothioates and to a method for producing said compounds.

To illustrate and characterize the chemical composition in a more precise manner the following formula is presented to define compounds within the scope of this invention The compounds of this invention are prepared by re acting phosphorus trichloride or R PC12where R is as described above with a ketone of the formula R R CO where R and R are as described above in the presence of a mercaptan R SH where R 'is as described above. These reactions are conveniently illustratedby the following equations: V

R1 SR:

In place of PC13 there can be used FBI; and the corresponding bromine'compounds can'thus be prepared.

Attempts were made to replace the ketone with an aldehyde to form the compound but in every case the reaction led to the formation of mercaptols and no material characterized by the above formula was recovered from the reaction.

Attempts to extend the scope of the reaction by substituting for P01 or R PCl a halophosphite represented by ROPCI or (RO) PCl where R represents lower alkyl did not result in phosphorylation of the ketone but led exclusively to reaction products of the mercaptan with the alkylhalophosphites.

When an alcohol, for example methyl alcohol or ethyl alcohol, was used in the reaction in place of a mercaptan no phosphorylation of the ketone occurred but dialkyl phosphite was formed. The ketone merely acted as an inert solvent with the reaction product formed being the same as if no ketone solvent had been employed. It is 3,346,669 Patented Oct. 10, 1967 rice apparent that the ketone did not react under the reaction conditions employed.

When PCl PBr or R PCl is added to a ketone, e.g. acetone, no noticeable reaction occurs such as color change, temperature rise or gas evolution. When 0.05 mole of P01 was added to 0.05 mole of acetone at 20 C. no reaction appeared to take place. A portion of this mixture was subjected to infrared scan between 2 and 15 microns to determine if any new absorption peaks appeared or any peaks disappeared when compared to the spectrumof each compound scanned separately. No new peaks appeared nor did any peaks disappear when the spectrum of the mixture was compared to the spectrum of the individual compounds. Scans of the infrared spectrum of the mixture after standing for 6 hours were repeated and compared with the spectrum of freshly prepared mixture and no change occurred between the two samples. This indicates that no apparent reaction occurred between acetone and PCl, in one case, PBr in another and R PCl (where R, was phenyl) in another example.

Since, when 3 moles of an alcohol are added to a mixture of PCl and acetone the well known phosphites are formed by this usual reaction, whether acetone is present or not as a solvent, it was unexpected to find when alcohol was replaced in the reaction with a mercaptan that the expected and known thiophosphites were not formed according to the reactions 5 P013 3R3SH P 2HCI RsCl SR; PCla 3R SH 1 8B; 31101 SRa Instead, the product isolated in high yields (-96%) is a phosphonate having the structure Both aliphatic and aliphatic-aromatic ketones lead only to monothio-substitution with mercaptans when the reaction is conducted at temperatures between 20 to +40 C.

What I have discovered is that a mercaptan induces a reaction between PCl or PBr or R PCl and aliphatic or aliphatic-aromatic ketones resulting in the formation of compounds not heretofore described.

The following examples are illustrative of this invention:

Example 1.S-ethyl-a-chloro-u-methyl propylphosphonochloridothioate Butanone (1 mole) and phosphorus trichloride (1 mole) were mixed at 0 C. and ethylmercaptan was added dropwise while the mixture was kept below 10 C. by cooling and agitation. Hydrogen chloride was liberated and reaction mixture became yellow. After the addition of ethylmercaptan was completed the mixture was allowed to warm up to 25 C. and agitation was continued until hydrogen chloride evolution ceased. Carbon tetrachloride (200 ml.) was added and the resulting solution Was washed with water until the solution was almost neutral (pH 6). The carbon tetrachloride solution Was dried over anhydrous sodium sulfate, filtered and the solvent was distilled off in vacuum. The remaining yellow oil (84% of theory) can be distilled, yielding the pure S-ethyl-achloro-a-methyl propylphosphonochloridothioate in 76% of theory, B.P. 0.15 80 C. 11 1.5186. Molecular Weight: 235.2 Calculated: Cl, 30.2%; P, 13.2%; S, 13.7%. Found: Cl, 29.7%; P, 13.2%; S, 14.0%.

Example 2 .S,S-dibutyl-u-chloro-a-phenyl ethylphosphonodithioate Acetophenone (0.2 mole) and phosphorus trichloride (0.2 mole) were mixed at room tempertaure and agitated for 1 hour. A slightly exothermic reaction occurred and the mixture became pale green.

Blltylmercaptan (0.4 mole) was added dropwise at 20 to the cooled and well agitated mixture. Reaction mixture was kept at 20 for 1 hour until hydrogen chloride evolution ceased and Was then heated for 1 hour at 90 until no more hydrogen chloride was liberated. The cooled mixture was diluted with 100 ml. carbon tetrachloride and washed with water until almost neutral. After drying the solution over anhydrous sodium sulfate and evaporation of the solvent, the low boiling components of the crude mixture were removed in vacuum of 0.04 mm. Hg at 90. The crude S,S-dibutyl-a-chloro-a-phenyl ethylphosphonodithioate was obtained as a yellow oil (11 1.5732) in 4 84% yield. Molecular weight: 364.5. Calculated: P, 8.6%; S, 17.6%. Found: P, 7.7%; S, 17.9%.

Example 3 .S-m'ethyl-a-chloroisopropyl phenylph0sphz'nothioate Phenyldichlorophospine (1 mole) and acetone (1 mole) were mixed at 10 C. and methylmercaptan (1 mole) was introduced within 3 to 4 hours. During this time the mixture was well agitated. The reaction mixture was then poured into ice water and the crude product was taken up in benzene, washed with'water until almost neutral, dried over anhydrous sodium sulfate and filtered. The solvent was removed under vacuum. The remainder crystallized after several hours. When recrystallized 'from ethyl alcohol, the pure S-methyl-a-chloroisopropyl phenyl phosphinothioate was obtained as a white solid, rn. 100. Molecular weight: 248.7. Calculated: Cl, 14.3%; P, 12.5%; S, 12.9%. Found: Cl, 14.0%; P, 12.3%; S, 12.8%.

Representative ketones which may be employed in this invention are dimethyl ketone, methyl ethyl ketone, diethyl ketone, methyl propyl ketone, methyl isopropyl ketone, ethyl butyl ketone, dipropyl ketone, methyl t-butyl ketone, isobutyl hexyl ketone, ethyl octyl ketone, acetophenone, phenyl acetone, p-chloroacetophenone.

Representative mercaptans which may be employed in this invention are methyl mercaptan, 'ethyl mercaptan, propyl mercaptan, isopropyl mercaptan, butyl mercaptan, sec-butyl mercaptan, t-butyl mercaptan, amyl mercaptan, hexyl mercaptan, octyl mercaptan, Z-ethyl hexyl mercaptan, chloromethyl mercaptan, chloroethyl mercaptan, dichloroethyl mercaptan, trichlor-oet-hyl mercaptan, and chloropropyl mercaptan.

- Examples of compounds of this invention prepared from the starting materials described above are listed in the Table 1. There is also listed the boiling and refractive indices where available.

TABLE 1 R1 0 SM ll R R4 Compound R R R R Boiling Point, Refractive No. C./mm. Hg Index Me Me C1 (48) 63/001 1. 5270 Me Et Cl 60/0.005 1. 5166 Me 150-?! 01 /002 1. 5055 Me Bu C1 80-85/0.04 1. 5085 Me sec-Bu Cl [0.02 1. 5058 Me iso-Bu 01 /004 1. 5052 E1: Me 01 75/0.15 1. 5265 Et Bu Cl 100/0.1 1. 5095 Et Et Cl /0.15 1. 5186 Pr Me Cl 94-98/0.02 1. 5200 Am Et 01 113/01 1. 5030 Bu Et Cl /0.2 1. 5097 Pr Et C1 1. 5070" Hex Et G1 1. 5010 -(CH Me 01 89/010 1.5450 (CH Bu Cl 118/0.15 1. 5232 -(CH Bu 01 /01 1. 5261 Me PhCH, Me Cl 1. 5736 Me PhCH Bu Cl 1. 5550 Me h Me Cl 1.5550

Me Bu C1 1. 5691 p-GlPh Bu 01 1. 5840 Me Me Ph Me Bu Ph 1 554-1 Me Me Me 1 5271 Me Me Pr 1 5153 Me C1(CHz)a C1 1. 5320" Me Pinanyl C1 1. 5326 E15 Cl(CHz)a-- C1 1. 5306 lso-Bu Me 01 1. 5163 lso-Bu Et C1 1. 5085 C1 1. 5300 C1 1.5229 Cl 1.5353 8% 1. 5386:: 1.5 5

-(CH Et 01 1.5375

POST-EMERGENCE HERBICIDAL ACTIVITY OF a-CHLOROALKYLPHOSPHINOTHIOATES X is a halogen selected from the class consisting of chlorine and bromine.

2. A compound of the formula where R is alkyl having 1 to 8 carbon atoms R is alkyl having 1 to 8 carbon atoms R and R taken together is -CH CH CI-I and A is halogen selected from the class consisting of chlorine and bromine X is a halogen selected from the class consisting of chlorine and bromine.

3. A compound of the formula R1 0 SR:

where R is alkyl having 1 to 8 carbon atoms R is alkyl having 1 to 8 carbon atoms R and R taken together is CH CH CH and n is a whole number from 1 to 3 inclusive R is alkyl having 1 to 8 carbon atoms B is phenyl X is a halogen selected from the class consisting of chlorine and bromine 4. A compound having the formula CH3 0 SCHzCHzCHzCHa 5. A compound having the formula CH 0 scam 6. A compound having the formula CH3 0 son;

8. A compound having the formula CH3 0 SCH:

C-P /l CH3 Cl A compound having the formula CH3 (:1 0 son;

ll Q 10. A compound having the formula CH2CH2 0 SCH;

11. A process of preparing alpha-halo thiophosphorus containing compounds which comprises reacting essentially one mole of an alkyl mercaptan having 1 to 8 carbon atoms and essentially one mole of a ketone having the formula where R is an alkyl radical having 1 to 8 carbon atoms and R is a hydrocarbon radical selected from the group consisting of alkyl having 1 to 8 carbon atoms, phenyl, chlorophenyl, and benzyl R and R taken together is CH CH CH and n is a whole number from 1 to 3 inclusive with essentially one mole of halophosphine selected from the group consisting of PX and R PX where R; is a hydrocarbon radical selected from the group consisting of alkyl having 1 to 8 carbon atoms, phenyl, and benzyl and X is chlorine or bromine.

12. A process according to claim 11 where R and R are independently alkyl radicals having 1 to 8 carbon atoms and R is an alkyl radical having 1 to 8 carbon atoms.

13. A process according to claim 11 where R and R are independently alkyl radicals having 1 to 8 carbon atoms and R is phenyl.

14. A process according to claim 12 where X is chlorme.

15. A process according to claim 13 where X is chlo- 16. A process of preparing the compound of claim 5 which comprises reacting essentially one mole of acetone and essentially one mole of phosphorus trichloride with essentially one mole of ethyl mercaptan.

17. A process of preparing the compound of claim 7 which comprises reacting essentially one mole of acetophenone and essentially one mole of phosphorus trichloride with essentially one mole of butyl mercaptan.

18. A process of preparing the compound of claim 6 which comprises reacting essentially one mole of acetone and essentially one mole of phosphorus tribromide with essentially one mole of methyl mercaptan.

No references cited.

CHARLES B. PARKER, Primary Examiner.

A. SUTTO, Assistant Examiner. 

1. A COMPOUND OF THE FORMULA
 11. A PROCESS OF PREPARING ALPHA-HALO THIOPHOSPHORUS CONTAINING COMPOUNDS WHICH COMPRISES REACTING ESSENTIALLY ONE MOLE OF AN ALKY MERCAPTAN HAVING 1 TO 8 CARBON ATOMS AND ESSENTIALLY ONE MOLE OF A KETONE HAVING THE FORMULA 